2. analog
  3. 1391623871

variance of +/- 10 Hz with 1 kHz test tone

I tried the Dr. Feickert Speed Tests iPhone app. I don't have his test record for the 3150 Hz track and the app says that you can use a 1000 Hz tone. I have a 1000 Hz tone from the Clearaudio sweep / burn-in record and tried that with the iPhone app running and showing microphone input on the meter. The app registered nothing. Has anyone else been able to get his iPhone app to work with a 1000 Hz tone? Are there any known problems with this app on iOS 7?

I used another iPhone app "Tuner Lite" and it showed my table to average right on for a F# 5 with the tuner set to concert A 440 Hz using the 1000 Hz tone. The Tuner Lite meter did fluctuate between the sharp and flat side (again within the two inner arrows, about +/- 10 Hz and were equidistant on both the flat and sharp side) during even time slices / cycles. Is this wow? Flutter? Good, bad or indifferent? Hole off center on test record? Strobe 33.3 reading looks to be dead on using the same Clearaudio disk with stylus on the record.

Phono setup is:
RP6 with GT ref subplatter and TTPSU
Herbie Mat Way Excellent II-2mm
Audio-Technica AT-33PTG/II 0.3mV MC
Salience / Jasmine LP2.0 mkII

Thanks,

Scott
sbrownnw
sbrownnw OP
704 posts
 
Second run of over 50 seconds was much better:

mean freq: 1001.4 Hz

raw freq
max deviation (relative): -.75% / +.68%
max deviation (absolute): -7.5 Hz / +6.8 Hz

lowpass-filtered freq
max deviation (relative): -.10% / +.05%
max deviation (absolute): -1.0 Hz / +.5 Hz
atmasphere's avatar
atmasphere
11,850 posts
 
You might see how it performs after its been running for 6 hours.
tonywinsc
583 posts
 
What is puzzling is such one sided numbers. Are you holding your iPhone in your hand when recording maybe? Place your iPhone on a table while recording. The raw is the actual frequency swing as the record rotates which includes eccentricity of the record hole. The program filters out this periodic side to side motion of the record since that is occuring at 0.556Hz. The filtered number is your actual turntable performance. The +0.05% looks good; but the -0.1% is troubling and I am wondering if the platter is really slowing down occasionally by that much.
tonywinsc
583 posts
 
PS. A record with the 3150Hz tone will be more accurate; if you could get one.
sbrownnw OP
704 posts
 
Yes, I am holding the phone. I will try it stationary next time.
More to discover